Skeleton crown and facing therefor.



E. F. GREER. SKELETON GROWN AND FACING THEREFOR. APPLIOATIOH FILED JULY v. 1913.

1,096,712, Patented May12,1914.

gmumd oz Emest F. Greer UNITED STATES FQQTENT OFFICE.

ERNEST F. GREEZR, OF IDABE-L, OKLAHOMA SKELETON CROWN AND FACING THEREFOR.

To all whom it may concern Be it known that I, ERNEST F. GREEK, a citizen of the United States, residing at Idabel, ,in the c'riun'ty o'f M'c'Cu'i'tain and State of Oklahoma, have invented certain new and useful Improvements in Skeleton Crowns and Facings Therefor'; and I do declare the following to be a full, clear, and exact descri tion of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to improvements in skeleton artificial tooth crowns and facings therefor.

The object of the invention is to proyide a skeleton crown which is simple and cheap, requiring only a very small quantity of gold to complete the crown, which avoids any gold being exposed at or near the gum margin, whichis practically impossible to break by internal force, and which saves a great deal of time in the application thereof.

\Vith these and other objects in view the invention consists of certain novel features of "construction, and the combination and arran'gemet of parts as will be more fully described and claimed.

In the accompanying drawings: Figure 1 represents a perspective view of the crown in the condition in which it will be placed on the market; Fig. 2 is a similar view of the facing used in connection with this improved skeleton crown; Fig. 3 is 'a side elevation of the crown after it has been finished by a dentist, with the exception of cementing the facing thereto; Fig. 4 is'a longitudinal vertical section of the completed tooth; Fig. 5 is a side elevation partly in section of a slightly different form of the invention.

In the embodiment illustrated a metallic post or pin 1 is shown of suitable size, shape and form to enter and approximately fit a prepared socket or canal in a natural tooth root. A metallic backing 2 extends longitudinally from the larger end of the pin 1 and a shoulder 3 extends laterally from the inner end of said backing at its junction with thepost at the front ot' said backing and is varied in lengtlraccording to the length of the crown facing securing pin to enter the porcelain facing at. the desired point. A similar shoulder 4 extends laterally from the back of the backing at its juncture with the post, said shtnlldci= being preferably semi-circular in sh a pc and which will be about the same Specification of Letters Patent. li pnc'a'fitn area my 7, 1915;. serial no. 777,761.

in order to cause the length in all cases. A facing securing pin 5 errands at ano'blique'angle from the front of the backing 2 adjacent the shoulder 3, said pi'n being inclined downwardly and adapted to enter a suitable socket in the facing to be described. The shoulders 3 .and 4 unite and form a continuous abutment at the base of the pin 1 and i'n'the inner face of said abutment is arranged a recess '6 designed to form a rim 6 and facilitate the formation of a joint with the natural 'to'o th root with -a minimum of grinding. The backing 2 is made longer than the facing to which it is to he applied and the free edge 7 thereof is made thin and is designed to be burnished over the cutting edge of the facing to provide a protection for said cutting edge and also to assist in holding the facing firmly inoperative osition.

This metal ic skeleton crow-n may be composed of ankrit or any other suitable substitute for platinum, or a portion of the metal may be composed of ankrite or any other suitable platinum substitute and gold.

may *be added where more desirable.

A facing 8 of porcelain is shown for use in conne tion with this improved skeleton crown and is provided on its rear face near its inner end with an offset 9 which is designed to engage the shoulder 3 of the crown and thereby relieve the fastening pin 5 from more or less strain. Adjacent the offset portion of the facing 8 is an obliquely disposed socket 10 positioned to receive the pin 5 when the parts are assembled. This facing 8 isdesigned to be cemented to the outer face of the backing 2 which renders them sanitary. If desired, the facings may be made interchangeable and a dentist can thus afford to keep a well assorted'stock of these crowns-on hand as they are adapted to take the place of 'full gold crowns, full porcelain crowns, post and plate, cast crowns and anchorage crowns in bridge -work or they may be converted into Rich;

mond crowns or used as when necessary these crowns may be easily converted into facings with backings, by cutting olf the post and inside shoulder;

In the use of this improved tooth the metallic and porcelain parts can be put to-.

gether and ground to fit the root of thetooth in thesame manner that an all porcelain crown is fitted. Very little grinding will be necessary on themctal shoulder as it is manufactured thick enough only to Patented May 12 1914.

allow; for grinding a joint and the facing is *}made full long at the gum margin to ,"adapt it to be properly fitted. 1 1

1 -A loser fitting joint can be made with this 'kind, of crown than with an all porce--- lain crown because, of thefact'thatthe facing may beremoved from time to timeto facing is then retrieved; The backing is 5 the metal 's'houlderto' th top -o edge which has been burnished over the edge then invested withoutlhaving to assemble the different parts and after nvesting, gold "solder is 'fio w'ed on the rear .faoe of the bac'king'and extends from;th'e fum line on the cutting of. the"faciiig., Thegold surface 'isthen rpolishe'dandthe" facing iscemented in position andthe crow'ni-s' complete ready for.

the metallic surface the facing by the'heat.

useas showneinYFig. 3Q The removal of the porcela'lnfacing vbefore flowing gold over prevents checking of The pin'5' penetrates the facin atthe thickest portion thereof at o'rnear t e longi- 'tudinal center thereof and at such an angle that the facing is not materially-weakened and thispeculiar positioning of the pin serves to hold the facing in position with the crown and root on the same principle that one post holds the Davis crown in the roo of a tooth and the facing is wedged lIi fI'Q I all sides except the front.

7 In Fig. 5 the post l is united with the lfront shoulder 35in advance of the backing 5? and said shoulder 3 is shown longer than 4G shoulder 4 to adapt it for-"a long tooth.

-'When these facings are assembled together in a bridge and it is desired to re move them before investing the bridge,- it

'is only necessary to heat one end of a stick of wax and stick to the front. surface of the Vfa'cin and lift not distorted.

itofi. whereby the bridge is I claim as my" invention:

A crown tooth comprising a metal post 0 and backing having a laterally extending shoulder, a facing-engaging pin extending r obliquely outward from said backing, and a facing having an offset at one end on one' face thereofv for engagement with said shoulder, and a socket for the reception of- Said v a t In testimony whereof I have hereunto set my hand in presence of two subscribing witne'sses.-

ERNEST F. GREEK. v Witnesses:

' H. M. KIRKPATRICK,

i R, MASSEY. 

